bland



(No Model.)

J. H. VAN NESS & M. A. BLAND.

I BLBOTRO MAGNETIC DENTAL PLU'GGBR. No. 310,099. Patented 1360.30, 1884.

UNITED STATES PATENT OEEICEO JAMES H. VAN NESS AND MORTIMER A. BLJQSD,OF ClrlARLO'lTlD, N. C.

ELECTRO-MAGNETlC DENTAL SPECIFICATION forming part of Letters Patent No.310,699, dated December 30, 1884.

Application tiled August is, 1891. (No model.)

To aZZ whom it may concern:

Be it known that we, J AMES II. in: Nnss and MORTIMER A. BLAND, ofCharlotte, in the State of North Carolina, have invented certain new anduseful Improvements in Electro-Magnetic Dental Pluggers or Mallets, ofwhich the following is a specification.

Our invention has reference to that kind of an electro-magnetic dentalplugger or mallet which is operated through the instrumentality of anautomatic circuit-breaking device.

Heretofore, so far as we are informed, the circuit-breaker has beenmounted on and carried by the instrument, forming, in fact, an integralpart of it. There are a number of ob jections to such an arrangement.The main disadvantage is the buzzing sound produced by thecircuit-breaker, which, being in close proximity to the patient, isextremely annoying. Furthermore, the instrument is some what complicatedas a whole, and it is dil'ticult to obtain the needed range ofadjustment of the stroke of the mallet.

XVith a view of obviating these and other objections, we have devisedour improvement, the main characteristics of which reside in the factthat the automatic circuit-breaker is distinct and separate from themallet or plunger, having no mechanical. connection therewith, the onlyconnection between the two being electrical, and such as afforded by thecircuitwire. In this way we are enabled to locate the circuit-breaker atany distance from the patient, even placing it in the next room, or inany other part of the building, as desired.

The system in which our invention is embodied comprises a severedcircuit, a circuitclosiug key, an electromagnetic dental plugger ormallet, an automatic circuit-breaker independent of and separate fromthe said mallet or plugger, and connections whereby, when the circuit isclosed by the key, the current from the generator or source ofelectricity will be directed alternately through the clectromagnet ofthe circuit breaker and the elec tro-magnet of the plugger or mallet.

Our invention will be readily understood by reference to theaccompanying drawing, which to some extent, represents diagrammaticallythe system hereinbefore referred to.

We have not deemed it necessary to represent in detail the specialconstruction of the dental plugger or mallet, for it can be, and is inpractice, similar to those now in use, save that it does not contain anautomatic circuitbreaker.

A represents the battery or source of electricity, B the automaticcii'cuitbreaker, G the electromagnetic dental plugger or mallet, andDthe circuit-closing key. In practice the circuit break er and batteryare usually located in one room, while the plugger or mallet andcircuit-closing key are in the room in which the patient is to beoperated on, and in convenient proximity to the operating-chair. Thecircuitclosing key is spring-acting, and normally in position tomaintain the circuit broken, and generally is so placed that it may beconveniently pressed by the foot of the op erator to close the circuit.The circuitbreaker consists of an electro niagnet, a, an armature, I),carried by an adjustably-weighted pivoted lever, c, which normally tendsto hold the armature away from its magnet. The armaturelever has a smalllaterally-projecting arm, 0, which engages the forked end of a vibratoryelbow-lever, d, pivoted at d, and provided at its upper end with acontact-strip, c, which plays between the contact-points f g.

The circuit connections are as follows: lole N of the battery isconnected by wirel to the contact-strip c. The other pole, S, of thebattery is connected by the wire 2 to the circuit-breakingelectro-magnet a, and thence by wire 3 to the key 1). The point 4, whichthe key makes contact with in order to close the circuit, is connectedby wire 5 to the contact point 1 From contact-point fleads a wire, 6,which connects with one end of the helix of the plugger-inagnet, theother end of which is connected by wire 7 to wire 2. Normally thecontactstrip e is in contact with g.

The drawing shows the position which the parts assume when the circuitis open. 'When by means of the key 1) the circuit is closed, theoperation is as follows: The circuit is first through the wire 5,contacts 9 f, wire 1, battery A, wire 2, electro-magnet a, wire 3, backto the circuit-closing key D. The magnet ais thus energized and attractsits armature b with the effect of vibrating the lever d in a directionto cause the strip 6 to break contact with g and to make contact with f.This cuts out the circuit-breaking magnet a, and the circuit is from thebattery through wire 1, contacts a f, wire 6, the helix of the plugger,wires 7 and 2 back to battery. The magnet a being cut out, its armaturedrops back to the position indicated in the drawing, breaking thecircuit 6 f and reinstating it through c 9, thus cutting out theplugger-magnet. In this way so long as the circuit is'elosed by means ofthe circuit-closing key D the circuit is com- .ileted-alteniatelythrough the circuit-breaking magnet and the plugger-magnet, thus producing the effect desired in this class of denj tal instruments.

e have described what we believe to be, on the whole, the bestembodiment of our invention. XVe do not, however, wish to be understoodas restricting ourselves to the special devices or arrangement of thesame herein represented, for it is manifest that the same may be variedin many particulars without departure from the spirit of the invention.

\Vhat we claim as new and of our own invention is 1. The combination, inan electric circuit, of an eleetro-magnetic plugger or mallet and anautomatic circuit-breaker for operating the same mechanically andindependent of and separate from said mallet, but electrically connected therewith, substantially as and for the purposes hereinbefore setforth.

2. The combination, in a circuit, of a circuit-closing key, anelectro-magnetic dental plugger or mallet, an automatic circuit-breakerindependent of and separate from said mallet, and electrical connection,substantially as described, whereby the circuit, when closed by the key,is completed alternately through the magnet of the circuit-breaker andmagnet of the mallet, substantially as and for the purposes set forth.

I11 testimony whereof we have hereunto set our hands this 18th day ofAugust, 1884.

JAMES H. VAN NESS. MORTIMER A. BLANI).

Witnesses:

J. R. HOLLAND, E. A. DICK.

